Generate parametric morphology profiles

This script demonstrates:

• Defining a resolution and grid for storing binned luminosity values.

• Generating and visualizing:

  • A 2D Gaussian profile.

  • A single annulus of a 2D Gaussian.

  • A point source.

  • A 2D Sersic profile.

  • A single annulus of a 2D Sersic profile.

Each resulting density distribution is visualised with matplotlib.

+------------------+
|    GAUSSIAN2D    |
+----------+-------+
| Attribute | Value |
+----------+-------+
| rho      | 0.30  |
+----------+-------+
| x_mean   | 0 kpc |
+----------+-------+
| y_mean   | 0 kpc |
+----------+-------+
| stddev_x | 1 kpc |
+----------+-------+
| stddev_y | 2 kpc |
+----------+-------+
+------------------------------------------------------+
|                   GAUSSIAN2DANNULI                   |
+------------+-----------------------------------------+
| Attribute  | Value                                   |
+------------+-----------------------------------------+
| rho        | 0.30                                    |
+------------+-----------------------------------------+
| n_annuli   | 6                                       |
+------------+-----------------------------------------+
| x_mean     | 0 kpc                                   |
+------------+-----------------------------------------+
| y_mean     | 0 kpc                                   |
+------------+-----------------------------------------+
| stddev_x   | 1 kpc                                   |
+------------+-----------------------------------------+
| stddev_y   | 2 kpc                                   |
+------------+-----------------------------------------+
| radii (6,) | 1.00e+00 kpc -> inf kpc (Mean: inf kpc) |
+------------+-----------------------------------------+
+---------------------------------------------------------------------------------------------------------------------------------------+
|                                                              POINTSOURCE                                                              |
+------------+--------------------------------------------------------------------------------------------------------------------------+
| Attribute  | Value                                                                                                                    |
+------------+--------------------------------------------------------------------------------------------------------------------------+
| cosmo      | FlatLambdaCDM(name=None, H0=<Quantity 70. km / (Mpc s)>, Om0=0.3, Tcmb0=<Quantity 0. K>, Neff=3.04, m_nu=None, Ob0=None) |
+------------+--------------------------------------------------------------------------------------------------------------------------+
| redshift   | 0.50                                                                                                                     |
+------------+--------------------------------------------------------------------------------------------------------------------------+
| offset_kpc | [2. 2.] kpc                                                                                                              |
+------------+--------------------------------------------------------------------------------------------------------------------------+
| offset_mas | [327.64275016 327.64275016] mas                                                                                          |
+------------+--------------------------------------------------------------------------------------------------------------------------+
+-----------------------------------------------------------------------------------------------------------------------------------------+
|                                                                SERSIC2D                                                                 |
+--------------+--------------------------------------------------------------------------------------------------------------------------+
| Attribute    | Value                                                                                                                    |
+--------------+--------------------------------------------------------------------------------------------------------------------------+
| amplitude    | 1.00                                                                                                                     |
+--------------+--------------------------------------------------------------------------------------------------------------------------+
| sersic_index | 2.00                                                                                                                     |
+--------------+--------------------------------------------------------------------------------------------------------------------------+
| theta        | 0.52                                                                                                                     |
+--------------+--------------------------------------------------------------------------------------------------------------------------+
| ellipticity  | 0.40                                                                                                                     |
+--------------+--------------------------------------------------------------------------------------------------------------------------+
| cosmo        | FlatLambdaCDM(name=None, H0=<Quantity 70. km / (Mpc s)>, Om0=0.3, Tcmb0=<Quantity 0. K>, Neff=3.04, m_nu=None, Ob0=None) |
+--------------+--------------------------------------------------------------------------------------------------------------------------+
| redshift     | 0.50                                                                                                                     |
+--------------+--------------------------------------------------------------------------------------------------------------------------+
| r_eff_mas    | 655.2855003153885 mas                                                                                                    |
+--------------+--------------------------------------------------------------------------------------------------------------------------+
| r_eff_kpc    | 4 kpc                                                                                                                    |
+--------------+--------------------------------------------------------------------------------------------------------------------------+
| r_eff        | 4 kpc                                                                                                                    |
+--------------+--------------------------------------------------------------------------------------------------------------------------+
| x_0          | 0 kpc                                                                                                                    |
+--------------+--------------------------------------------------------------------------------------------------------------------------+
| y_0          | 0 kpc                                                                                                                    |
+--------------+--------------------------------------------------------------------------------------------------------------------------+
+-----------------------------------------------------------------------------------------------------------------------------------------+
|                                                             SERSIC2DANNULI                                                              |
+--------------+--------------------------------------------------------------------------------------------------------------------------+
| Attribute    | Value                                                                                                                    |
+--------------+--------------------------------------------------------------------------------------------------------------------------+
| amplitude    | 1.00                                                                                                                     |
+--------------+--------------------------------------------------------------------------------------------------------------------------+
| sersic_index | 2.00                                                                                                                     |
+--------------+--------------------------------------------------------------------------------------------------------------------------+
| theta        | 0.52                                                                                                                     |
+--------------+--------------------------------------------------------------------------------------------------------------------------+
| ellipticity  | 0.40                                                                                                                     |
+--------------+--------------------------------------------------------------------------------------------------------------------------+
| cosmo        | FlatLambdaCDM(name=None, H0=<Quantity 70. km / (Mpc s)>, Om0=0.3, Tcmb0=<Quantity 0. K>, Neff=3.04, m_nu=None, Ob0=None) |
+--------------+--------------------------------------------------------------------------------------------------------------------------+
| redshift     | 0.50                                                                                                                     |
+--------------+--------------------------------------------------------------------------------------------------------------------------+
| n_annuli     | 5                                                                                                                        |
+--------------+--------------------------------------------------------------------------------------------------------------------------+
| r_eff_mas    | 655.2855003153885 mas                                                                                                    |
+--------------+--------------------------------------------------------------------------------------------------------------------------+
| r_eff_kpc    | 4 kpc                                                                                                                    |
+--------------+--------------------------------------------------------------------------------------------------------------------------+
| r_eff        | 4 kpc                                                                                                                    |
+--------------+--------------------------------------------------------------------------------------------------------------------------+
| x_0          | 0 kpc                                                                                                                    |
+--------------+--------------------------------------------------------------------------------------------------------------------------+
| y_0          | 0 kpc                                                                                                                    |
+--------------+--------------------------------------------------------------------------------------------------------------------------+
| radii (5,)   | 2.00e+00 kpc -> inf kpc (Mean: inf kpc)                                                                                  |
+--------------+--------------------------------------------------------------------------------------------------------------------------+

import matplotlib.pyplot as plt
import numpy as np
from astropy.cosmology import FlatLambdaCDM
from unyt import kpc, unyt_array

from synthesizer.parametric import (
    Gaussian2D,
    Gaussian2DAnnuli,
    PointSource,
    Sersic2D,
    Sersic2DAnnuli,
)

# Common settings
resolution = 0.05 * kpc
npix = (500, 500)
x = unyt_array(np.linspace(-10, 10, npix[0]), "kpc")
y = unyt_array(np.linspace(-10, 10, npix[1]), "kpc")
xx, yy = np.meshgrid(x.value, y.value) * kpc

cosmo = FlatLambdaCDM(H0=70, Om0=0.3)
z = 0.5

# 2D Gaussian
gauss = Gaussian2D(
    x_mean=0 * kpc,
    y_mean=0 * kpc,
    stddev_x=1 * kpc,
    stddev_y=2 * kpc,
    rho=0.3,
)
print(gauss)
gauss_grid = gauss.get_density_grid(resolution, npix)

# Gaussian annulus
radii = unyt_array([1.0, 3.0, 5.0, 7.0, np.inf], "kpc")
gauss_ann = Gaussian2DAnnuli(
    x_mean=0 * kpc,
    y_mean=0 * kpc,
    stddev_x=1 * kpc,
    stddev_y=2 * kpc,
    radii=radii,
    rho=0.3,
)
print(gauss_ann)
gauss_ann_grid = gauss_ann.get_density_grid(resolution, npix, annulus=1)

# Point source at (2,2) kpc
ps = PointSource(
    offset=unyt_array([2.0, 2.0], "kpc"),
    cosmo=cosmo,
    redshift=z,
)
print(ps)
ps_grid = ps.get_density_grid(resolution, npix)

# 2D Sersic (n=2, e=0.4, θ=30°)
sersic = Sersic2D(
    r_eff=4 * kpc,
    amplitude=1.0,
    sersic_index=2.0,
    x_0=0 * kpc,
    y_0=0 * kpc,
    theta=np.deg2rad(30),
    ellipticity=0.4,
    cosmo=cosmo,
    redshift=z,
)
print(sersic)
sersic_grid = sersic.get_density_grid(resolution, npix)

# Sersic annulus (note that infinity is always added as the last radius)
s_radii = unyt_array([2.0, 4.0, 6.0, 8.0], "kpc")
sersic_ann = Sersic2DAnnuli(
    r_eff=4 * kpc,
    radii=s_radii,
    amplitude=1.0,
    sersic_index=2.0,
    x_0=0 * kpc,
    y_0=0 * kpc,
    theta=np.deg2rad(30),
    ellipticity=0.4,
    cosmo=cosmo,
    redshift=z,
)
print(sersic_ann)
sersic_ann_grid = sersic_ann.get_density_grid(resolution, npix, annulus=1)

# Plot everything in a 2×3 grid
fig, axes = plt.subplots(2, 3, figsize=(12, 8))
plots = [
    (gauss_grid, "Gaussian2D"),
    (gauss_ann_grid, "Gaussian2DAnnuli (outer shell)"),
    (ps_grid, "PointSource"),
    (sersic_grid, "Sersic2D (n=2)"),
    (sersic_ann_grid, "Sersic2DAnnuli (outer shell)"),
]
for ax, (grid, title) in zip(axes.flat, plots):
    im = ax.contourf(xx, yy, grid, levels=50)
    ax.set_title(title)
    ax.set_xlabel("X (kpc)")
    ax.set_ylabel("Y (kpc)")
    fig.colorbar(im, ax=ax, label="Density")

# hide the empty subplot
axes.flat[-1].axis("off")

plt.tight_layout()
plt.show()